This invention relates to an apparatus for the preparation of seams which are to be pressed. More particularly, the apparatus is to be used on pressing machines and, especially, in machines which are a combination of pressing machines and sewing machines.
Pressing machines for the pressing of seams are known in which the legs of the seam must be opened and folded manually. In most cases, stabilization by means of a hand pressing iron is needed. Afterwards, the item having the seam is introduced into the pressing machine and pressed. Manual preparation of the seam for pressing adds to the time and, hence, the cost of the entire operation.
An improvement was provided in the prior art in the form of so-called "throughput pressers" which operate either continuously or intermittently. The throughput pressers usually consist of two rotary transporting bands which are pressed against each other, one of the bands being provided outside the pressing zone with an elongation for the correct feeding of the fabric items. In these machines, a pressing foot is lowered upon the seam after the seam legs are separated manually, the foot continuously folding the seam legs which, of course, are short, during the further transport of the fabric.
While this latter type of machine is an improvement in that less expenditure of time is required, nonetheless a large amount of manual labor is still necessary. Moreover, when pressing a curved seam with these machines, manual assistance is still needed because there are no guiding means. The absence of a suitable guiding means is particularly noticeable when a sewing means is combined with the pressing machine.
Consequently, in the prior art, there exist a number of apparatuses which make it possible to directly couple the sewing means and the pressing machine, thereby making continuous operation possible. Basically, each of these apparatuses includes two guide rails, disposed on opposite sides of the fabric pressing foot, the guide rails being parallel to the working plane of the sewing machine and perpendicular to the pressing plane. At the ends of the rails facing the sewing machine are located both pressing surfaces at a predetermined distance from the working plane of the sewing machine. The guide rails form a vertical plane just before the transition to the pressing elements, which causes the folding over of the short legs of the seam onto the respective fabric parts. It is assumed that well-known transport means will guide the fabric parts along the rails without distorting the fabric parts.
A disadvantage of the latter apparatus is the position of the guide rails immediately adjacent the fabric pressing foot. This is particularly disadvantageous in the case of the guide rail at the right side of the fabric pressing foot because the right rail must be located extremely close to the foot in order to assure secure guiding of the relatively short legs of the seam. Consequently, it is very difficult to put the fabric parts underneath the pressing foot. Moreover, the seam legs tend to slip out of the guide because the seam legs are relatively short. A relatively narrow guide slot is needed for the seam in order to prevent such a slipping but such a slot is not good for the transport of fabric parts which are connected by curved seams. In particular, the narrow slot offers considerable resistance to the seam because relative to the curvature of the seam it is geometrically a chord.